Means for transferring fluids in an absorption refrigeration system



27, .1965 F. M. WALKER 93, 81

MEANS FOR TRANSFERRING FLUIDS IN AN ABSORPTION REFRIGERATION SYSTEMFiled May 21, 1965 1 N VENTOR.

United States Patent 3,293,881 MEANS FOR TRANSFERRING FLUIDS IN ANABSORPTION REFRIGERATION SYSTEM Frank M. Walker, sass NW. 46th, OklahomaCity, Okla. 73112 Filed May 21, 1965, Ser. No. 458,841 9 Claims. (Cl.62476) This invention relates to absorption refrigeration systems and inparticular to means for pumping fluids from the low pressure portion tothe high pressure portion of a two pressure absorption refrigerationsystem.

In the conventional two pressure absorption refrigeration system,circulation of the refrigerant fluid throughout the system isaccomplished by the pressure differentials between different portions ofthe system. At one point in such a system, conventionally at thegenerator, energy is introduced to the system in the form of heat atelevated temperature providing a high pressure refrigerant vaporconventionally delivered to a condenser wherein the vapor is condensedto a liquid. The liquifled refrigerant is then delivered to anevaporator wherein it evaporates, drawing the heat of vaporization fromthe exterior of the refrigeration system and thereby effecting thedesired refrigeration effect. The low pressure vaporized refrigerant isdelivered from the evaporator to an absorber wherein it is absorbed by aliquid and is delivered from the absorber to the generator as a solutionto be reheated to again provide high pressure refrigerant vapor to beginthe cycle over again. The present invention is concerned with a new andimproved means for use in such an absorption refrigeration system forpumping the low pressure solution from the absorber to the generatoragainst the high pressure of the vaporized refrigerant therein.

A principal feature of the invention is the provision of a new andimproved means for pumping refrigerant in an absorption refrigerationapparatus.

Another feature is the provision of such a pumping means in anabsorption refrigeration system having a first portion containing highpressure fluid and a second portion containing low pressure fluid, thepumping means including a pump connected between the first and secondportions of the system for pumping fluid through and between the highpressure portion and low pressure portion, and means using a portion ofthe energy of the high pressure fluid for operating the pump.

A further feature of the invention is the provision of such a pump meanswhich is simple in design and economically constructed, having fewmoving parts, thus providing extended maintenance-free service.

Still another feature is the provision of such a pump means arranged forcontinuous functioning notwithstanding fluid pressure variations withinthe system due to ambient temperature changes.

Another feature is the provision of a pumping mechanism which alsoserves as the pressure reducing valve for controlling flow of theabsorption fluid from the generator to the absorber.

A yet further feature of the invention is the provision of such pumpmeans which utilizes effectively minimum power, and which issubstantially silent in operation.

Other features and advantages of the invention will be apparent from thefollowing description taken in connection with the accompanying drawingwherein:

FIGURE 1 is a schematic view of a refrigeration system including a pumpmeans embodying the invention, the pump means being shown as near theend of one half cycle of operation thereof. FIGURE 2 is a view of thepump shown in FIGURE 1 but with the pump means shown as near the end ofthe other half cycle of operation thereof.

In the embodiment of the invention as disclosed in the drawing, anabsorption refrigeration system generally designated 10 includes agenerator 11, a condenser 12, an evaporator 13, and an absorber 14, allof conventional construction.

Illustratively, the refrigerant may comprise ammonia and the liquidabsorbent for absorbing the refrigerant in,

the system may comprise water. The present invention is concerned with anew and improved pump generally designated 15 for pumping water which isrich in ammonia refrigerant, hereafter referred to as x -liquid, fromthe absorber 14 to the generator 11 wherein the x -liquid is heated bythe burner 69 to vaporize the ammonia refrigerant for delivery throughconduit 64 to the condenser 12 where it is condensed to liquid. Thecondensed refrig erant is delivered from the condenser 12 to restrictortube 49 which reduces the pressure of the liquid ammonia as it flowsinto the evaporator 13 where it vaporizes and flows through conduit 68into the absorber 14 where it is absorbed by the solution therein.

The water which is Weak in ammonia refrigerant as a result of vaporizingthe ammonia vapor therefrom, and which is hereafter refered to as x-liquid, is delivered from the generator 11 through a portion of thepump means 15 wherein a portion of the high pressure vapor energy in thegenerator 11 is utilized hydraulically for operating the pump means 15through one half cycle. Similarly, high pressure vapor from thegenerator 11 is delivered directly through another portion of the pumpmeans 15 utilizing a portion of the high pressure vapor energy in thegenerator 11 directly for operating the pump means 15 through the otherhalf cycle.

Control of cycling the pump means 15 is obtained by means of a suitableconventional electric timer 16 for continued alternate opening andclosing of selected solenoid valves 19, 2t), 29 and 34 at preselectedtime intervals to effect a predetermined g.p.m. rate of delivery by thepump means 15. More specifically, pump means 15 includes a pump 18;solenoid valves 19, 20, 29 and 30; check valves 55, 57, 61 and 63; andelectric timer 16. The outer housing of pump 18 is defined by a firstcylindrical portion 21 defining a first space 21a and a second portion22, diametrically larger but having the same length of portion 21,defining a second space 22a. A partition 34 separates space 21a fromspace 22a. A piston 23 is slidable in housing portion 21 and anincreased diameter piston 25 is slidable in housing portion 22. A shaft28, slightly longer than either space 21a or 22a, passes throughpartition 34 and is fastened at one end to piston 23 and the other endfastened to piston 25. As shown, piston 23 is slidably sealed to housingportion 21 by a piston ring 32, piston 25 is slidably sealed to housingportion 22 by a piston ring 31, and shaft 28 is slidably sealed topartition 34 by a shaft seal 35.

Low pressure x -liquid is delivered from absorber 14 into space 22a ofpump 18 between piston 25 and partition 34 by means of a conduit 54provided with a check valve 55 precluding reverse flow therethrough.This space will hereinafter be referred to as space A. The x -liquid isdelivered from space A of pump 18 to generator 11 by means of a conduit56 leading from space A and provided with a check valve 57 precludingreverse flow therethrough. Low pressure x liquid is also delivered fromabsorber 14 into space 21a of pump 18 between piston 23 and partition 34by means of conduits 54 and 60 provided with a check valve 61 precludingreverse flow therethrough. This space will hereinafter be referred to asspace B. The x -liquid is delivered from space B of pump 18 to thegenerator 11 by means of conduits 62 and 56 leading from space B andprovided with a check valve 63 precluding reverse flow therethrough.High pressure x liquid is delivered from generator 11 into space 22a ofpump 18 between piston 25 and end wall 36 by means of a conduit 58 andprovided with a solenoid valve 20 controlling flow therethrough. Thisspace will hereinafter be referred to as space C. The x -liquid isdelivered from space C of pump 18 to the absorber 14 by means of aconduit 59 leading from space C and provided with a solenoid valve 19controlling flow therethrough. High pressure vapor is delivered from thegenerator 11 into space 21a of pump 18 between piston 23 and end wall 65by means of conduits 64 and 66 and provided with a solenoid valve 30controlling flow therethrough. This space will hereinafter be referredto as space D. The high pressure vapor is released from space D of pump18 to the absorber 14 by means of conduits 67 and 68 leading from spaceD and provided with a solenoid valve 29 controlling flow therethrough.

The cycle of operation of the refrigeration system is initiated bysupplying heat energy, such as burner 69, to the generator 11 andelectrical energy through lines L1 and L2 to the timer 16. The heat ofburner 69 applied to the generator 11 produces a high vapor pressure inthe generator 11 and condenser 12 as compared to a lower vapor pressurepresent in the evaporator 13 and absorber 14. Timer 16 cyclicallysupplies electrical energy simultaneously through lines H1 and H2 tosolenoid valves and 29, opening them for a preselected time, and thenreverses supplying electrical energy simultaneously through lines H1 andH3 to solenoid valves 19 and 30, opening them for a preselected time. Itis to be noted that solenoid valves 19, 20, 29 and 30 are opened whenenergized and olosed when de-energized. Also, the combination of pairedsolenoid valves 19 and 20 together with T 70 co-act to form a three-wayvalve. Similarly, solenoid valves 29 and 30 together with T 71 co-act toform a three-way valve. Although I have shown the preferred form, it isunderstood that any type of controllable three-way valve may besubstituted. For in stance, pneumatic or hydraulically operatedthree-way valves could be used in place of the paired solenoid valvesshown and described.

Assuming the timer 16 has initiated the energizing of solenoid valves 20and 29, opening them, high pressure x -liquid enters space C from thegenerator 11, while at the same time, high pressure vapor alreadypresent in space D is released into the absorber 14. The difference ofthese new opposing pressures, in space C and space D, acting on theopposite ends of shaft 28, produce a thrust on shaft 28, forcing themovement of pistons 23 and downward. During the downward movement ofpistons 23 and 25, x -liquid in space A is forced into the generator 11through check valve 57 and conduit 56, while at the same time, x -liquidis drawn from the gen erator 11 into space C through conduit 58,solenoid valve 20 and T 70. Also, during the downward movement ofpistons 23 and 25, x -liquid is drawn into space B through conduits 54and 60 and check valve 61 while at the same time, vapor in space D flowsinto the absorber 14 through T 71 and solenoid valve 29, conduits 67 and68. At the end of the downward movement of pistons 23 and 25, the pumphas the position shown in FIGURE 1. The timer 16 now reverses, accordingto a preselected time interval, which initiates the energizing ofsolenoid valves 19 and 390 through lines H1 and H2, opening them. Highpressure vapor enters space D through conduits 64 and 66, solenoid valveand T 71. The hydraulically high pressure x -liquid in space Cimmediately becomes low pressure hydraulic x -liquid. The difference ofthese new opposing pressures in spaces C and D, acting on the oppositeends of shaft 28, produce thrust on shaft 28, forcing the movement ofthe pistons 23 and 25 upward. During the upward movement of pistons 23and 25, x liquid is forced out of space C into the absorber 14 through T70, solenoid valve 19 and conduit 59, while at the same time, x -liquidis drawn into space A from the absorber 14 through conduit 54 and checkvalve 55. Also, during the upward movement of pistons 23 and 25,

x -liquid is forced out of space E into the generator 11 through checkvalve 63 and conduits 62 and 56.

It should be noted that spaces 21a and 22a in pump 18 are soproportioned that a larger volume is provided for pumping x -liquid fromthe absorber 14 to the generator 11 than is provided for pumping x-liquid from the generator 11 to the absorber 14. This is necessarybecause the volume of liquid in the generator 11 is constantlydecreasing, while at the same time, the volume of liquid in the absorber14 is substantially increasing an equal amount during the operation ofthe refrigeration system, due to the flow of ammonia through thecondenser 12 and evaporator 13 as well as through chamber D of pump 18.By utilizing both space A and space B for moving x -liquid from theabsorber 14 to the generator 11, but utilizing only space C for moving x-liquid from the generator 11 to the absorber 14, a simple and accuratemeans is provided to automatically balance the liquid levels in theabsorber 14 and generator 11 at all times during operation of therefrigeration system. Also, it should be noted that it is possible touse either a preselected or a variable g.p.m. rate of delivery by pumpmeans 15. The thrust developed by the shaft 28 will automaticallyincrease or decrease with an increase or decrease of ambienttemperature. For example, the pressure differential between thegenerator-condenser and the absorber-evaporator of the system will rangefrom 190 p.s.i.g. at 70 F. to 260 p.s.i.g. at F. ambient. The thrustdeveloped by shaft 28 is calculated by the formula, T=A(P1P2), where Tthrust, A='cross sectional area of the shaft 28, Pl=pressure of thegenerator-condenser, and P2=pressure of the evaporator-absorber.Therefore, the selection of a .25 sq. in. cross sectional area shaft 28would develop a thrust having a range of 47 /2 lbs. at 70 F. ambient to65 lbs. at 95 F. ambient. Therefore, pistons 23 and 25 are forced tomove faster by the shaft 28 as the ambient temperature increases orvice-versa. It is shown by the above that it is possible to provide adual modulating control (not shown) for simultaneously increasing ordecreasing the speed of timer 16 and the B.t.u. input to burner 69 inresponse to increased or decreased load demand to automatically modulatethe output of the refrigeration system. Although I have shown thepreferred arrangement in the drawing and in the description of a timer16 having a preselected constant speed for control of said solenoidvalves 19, 20, 29 and 30 to produce a predetermined constant g.p.m. rateof delivery of pump means 15, it is used merely for simplicity ofdescription and is not meant to limit the spirit or scope of theinvention. Also, while I have shown a single embodiment of the inventionas herein illustrated and described, it will be understood thatmodifications may be made in the construction and arrangement ofelements without departing from the spirit or scope of the invention.For instance, diaphragms may be substituted for the pistons 23 and 25shown. Also, any combination of refrigerant and absorbent for therefrigerant may be substituted for the ammonia and water hereindescribed. Therefore, without limitation in this respect, the inventionis defined by the following claims.

I claim:

1. In an absorption refrigeration system having a first portionincluding a generator containing high pressure vapor and solution and acondenser containing high pressure refrigerant vapor and liquid, and asecond portion including an absorber containing low pressure vapor andsolution and an evaporator containing low pressure refrigerant vapor andliquid, apparatus comprising: a pump having means defining a firstchamber and a first displacement member reciprocable in said firstchamber for displacement of fluid in said chamber, a second chambercoaxially aligned with the said first chamber and being diametricallysmaller than said first chamber and a second displacement memberreciprocable in said second chamber for displacement of fluid in saidchamber; a shaft slidably passing through the common end walls of saidchambers and fastened at one end thereof to said first displacementmember and fastened at the other end thereof to the said seconddisplacement member for reciprocating said displacement members as aunit; first flow passage means communicating with said first chamber atone side of said first displacement member and with the said absorberand said generator for delivering a predetermined volume of x -liquidfrom said absorber to said first chamber during one movement of the saidshaft and displacement members and delivering the said volume of x-liquid therefrom to said generator during the opposite movement of saidshaft and displacement members; a second flow passage meanscommunicating with said first chamber at the opposite side of the saidfirst displacement member and with the said absorber and said generatorand including a valve responsive to electrical impulse for delivering apredetermined volume of high pressure x -liquid from said generator tosaid first chamber at the opposite side of the said first displacementmember during said opposite movement of the said shaft and displacementmembers and delivering said volume of x -liquid therefrom to saidabsorber during said one movement of the said shaft and displacementmembers; a third flow passage means communicating with the secondchamber at one side of the said second displacement member and with thesaid absorber and said generator for delivering a predetermined volumeof x -liquid from said absorber to said second chamber during saidopposite movement of said shaft and displacement members and deliveringsaid volume of x -liquid therefrom to said generator during said onemovement of the said shaft and displacement members; a fourth flowpassage means communicating with said second chamber at the oppositeside of the said second displacement member and with the said generatorand absorber and including a valve responsive to electrical impulse fordelivering high pressure vapor to said second chamber at the oppositeside of the said second displacement member during said one movement ofthe said shaft and displacement members and delivering the high pressurevapor therefrom to said absorber during said opposite movement of saidshaft and displacement members; and an electric timer means cyclicallyenergizing said valves connecting said first and second chambersalternately and oppositely with the said high pressure and said lowpressure portions of the system to reciprocate the said shaft anddisplacement members.

2. In an absorption refrigeration system having a first portionincluding a generator containing high pressure vapor and solution and acondenser containing high pressure refrigerant vapor and liquid, and asecond portion including an absorber containing low pressure vapor andsolution and an evaporator containing low pressure refrigerant vapor andliquid, apparatus comprising: a pump for circulating solution throughand between the first and second portions of the system and including afirst closed cylinder having an outer end and an inner end and a port atthe outer end and an inlet and outlet adjacent the inner end; a firstreciprocable piston in the first cylinder forming an outer chamber andan inner chamber therein; a second closed diametrically smaller cylinderthan said first cylinder having an outer end and an inner end and a portat the outer end and an inlet and outlet adjacent the inner endco-axially sealed to the inner end of the said first cylinder; a secondreciprocable piston in the second cylinder forming an outer chamber andan inner chamber therein; a shaft slightly longer than either of saidfirst or second cylinders slidably passing through the common end wallbetween said cylinders and having one end thereof fastened to the saidfirst piston and the other end thereof fastened to the said secondpiston effecting united inverse volume changes of the said outerchambers and inner chambers of the said cylinders upon reciprocation ofthe said pistons and shaft; a first flow control valve operationallyresponsive to electrical impulse having an inlet communicating with thehigh pressure solution in the said generator and an outlet communicatingwith the said absorber and a port communicating with the said port tothe outer end of the said first cylinder for selectively delivering apredetermined volume of solution from the said generator to the outerchamber of the said first cylinder upon one movement of the said pistonsand shaft and delivering said volume of solution from the said outerchamber to the said absorber upon the opposite movement of the saidpistons and shaft; a second flow control valve operationally responsiveto electrical impulse having an inlet communicating with the highpressure vapor in the said condenser-generator and an outletcommunicating with the said absorber and a port communicating with thesaid port to the outer end of the second cylinder for selectivelydelivering a predetermined volume of high pressure vapor from the saidgenerator to the outer chamber of the said second cylinder upon saidopposite movement of the said pistons and shaft and delivering the saidvolume of vapor from the said outer chamber to the said absorber uponthe said one movement of the pistons and shaft; a first check valvehaving an inlet communicating with the absorber and an outletcommunicating with the inlet to the inner chamber of the said firstcylinder for flow of solution from the said absorber into the said innerchamber upon said opposite movement of the pistons and shaft andprecluding reverse flow therethrough; a second check valve having aninlet communicating with the absorber and an outlet communicating withthe inner chamber of the said second cylinder for flow of solution fromthe said absorber into the said inner chamber upon said one movement ofthe pistons and shaft and precluding reverse flow therethrough; a thirdcheck valve having an inlet communicating with the inner chamber of thesaid first chamber and an outlet communicating with the said generatorfor flow of solution from the said inner chamber to the generator uponthe one movement of the said pistons and shaft and precluding reverseflow therethrough; a fourth check valve having an inlet communicatingwith the inner chamber of the said second chamber and an outletcommunicating with the said generator for flow of solution from the saidinner chamber to the generator upon the opposite movement of the saidpistons and shaft and precluding reverse flow therethrough; and anelectric timer switch for selectively energizing said control valves forpreselected time intervals to connect said first cylinder outer chamberalternately to the said high pressure solution in the said generator andthe said absorber and oppositely connecting the said second cylinderouter chamber alternately to the said high pressure vapor in thegenerator-condenser and the said absorber for utilizing a portion of thehigh pressure vapor energy produced in the system to alternately developthrust on the opposite ends of the said shaft so as to reciprocate thesaid pistons.

3. The combination with an absorption refrigeration system of thedifferential pressure type wherein a solution of refrigerant and anabsorbent circulate, a generator disposed in the high pressure side ofthe system, an absorber disposed in the low pressure side of the system,conduits forming a circuit for flow of refrigerant and absorbent throughand between the generator and absorber, of a pump interposed in saidcircuit for forcing circulation of fluids through the circuit,comprising a first solution displacement means, a second solutiondisplacement means, a power piston interconnecting the said first andsecond solution displacement means and having one end thereof exposed toexisting pressures in the first solution dis placement means and theopposite end thereof exposed to existing pressures in the secondsolution displacement means, and means for alternately communicating onesolution displacement means to the high pressure side of the systemwhile simultaneously communicating the other solution displacement meansto the low pressure side of the system to actuate the piston andsolution displacement means by system forces acting on opposite ends ofthe piston.

4. The invention set forth in claim 3, wherein the said last mentionedmeans includes electrically operated valve means controllingcommunication between the said first and second solution displacementmeans and the high and low pressure sides of the system, an electriccircuit for operating said valve means, and an electric cam actuatedswitch in said circuit to control the circuit.

5. In an absorption refrigeration system having a first portioncontaining high pressure fluid and a second portion containing lowpressure fluid, apparatus comprising: a double action pump for pumpingfluid through and between the first and second portions of the systemincluding a housing having a partition therein forming a first chamberhaving an inlet and an outlet adjacent the partition, and a portopposite the partition, and a second chamber having an inlet and anoutlet adjacent the partition, and a port opposite the partition; afirst fluid displacement piston in the first chamber reciprocable towardand from the said partition; a second fluid displacement piston in thesecond chamber reciprocable toward and from the said partition; firstpassage means for delivering fluid from the said second portion of thesystem to said inlets upon spacing of said pistons from said partition;a second passage means for delivering fluid from said outlets to saidfirst portion of the system upon juxtaposing of said pistons toward saidpartition; a power piston slidably passing through the said partitionand fastened to the said fluid displacement pistons; and means forselectively applying system pressure differentials on opposite ends ofsaid power piston for cyclically reciprocating said fluid displacementpistons at preselected time intervals.

6. In an absorption refrigeration system as defined in' claim 5 furthercharacterized by said last mentioned means comprising; a third passagemeans including a control valve for selectively communicating the portin the said first chamber with either of the said first or secondportions of the system; a fourth passage means including a control valvefor selectively communicating the port in the said second chamber witheither of the said first or second portions of the system; and controlmeans for selectively controlling said control valves.

7. In an absorption refrigeration system as defined in claim 6 furthercharacterized by said control valve being electrically operated.

8. In an absorption refrigeration system as defined in claim 7 furthercharacterized by said control means comprising an electric circuitincluding the said electrically operated valves, and an electric timeractuated switch in the said circuit to control the circuit.

9. In an absorption refrigeration system of the differential pressuretype wherein a solution of refrigerant and an absorbent circulate,refrigerant vapor generator means having a vapor outlet, a solutioninlet and a solution outlet, absorber means having a solution inlet,solution outlet and a refrigerant vapor inlet, a condenser having aninlet connected to the vapor outlet of said generator means and anoutlet; an evaporator having an inlet connected to said condenser outletand an outlet connected to said re frigerant vapor inlet of saidabsorber means, a first pump means, a second pump means, said first andsecond pump means conveying solution from said absorber solution outletto said generator solution inlet, said first pump means having a drivingfluid inlet connected to the solution outlet of said generator means anda driving fluid outlet connected to the solution inlet of said absorbermeans, said second pump means having a driving fluid inlet connected tothe vapor outlet of said generator means and a driving fluid outletconnected to the refrigerant vapor inlet of said absorber means, andmeans interconnecting the said first and second pump means foralternately operating one said pump means by forces developed in theother said pump means.

References Cited by the Examiner UNITED STATES PATENTS 2,929,222 3/1960Lang 62487 X 2,930,204 3/1960 Lang 62--488 X 3,046,756 7/1962 Whitlow etal. 62141 FOREIGN PATENTS 593,548 3/1934 Germany. 840,249 5/1952Germany. 708,482 5/1954 Great Britain.

LLOYD L. KING, Primary Examiner.

3. THE COMBINATION WITH AN ABSORPTION REFRIGERATION SYSTEM OF THEDIFFERENTIAL PRESSURE TYPE WHEREIN A SOLUTION OF REFRIGERANT AND ANABSORBENT CIRCULATE, A GENERATOR DISPOSED IN THE HIGH PRESSURE SIDE OFTHE SYSTEM, AN ABSORBER DISPOSED IN THE LOW PRESSURE SIDE OF THE SYSTEM,CONDUITS FORMING A CIRCUIT FOR FLOW OF REFRIGERANT AND ABSORBENT THROUGHAND BETWEEN THE GENERATOR AND ABSORBER, OF A PUMP INTERPOSED IN SAIDCIRCUIT FOR FORCING CIRCULATION OF FLUIDS THROUGH THE CIRCUIT,COMPRISING A FIRST SOLUTION DISPLACEMENT MEANS, A SECOND SOLUTIONDISPACEMENT MEANS, A POWER PISTON INTERCONNECTING THE SAID FIRST ANDSECOND SOLUTION DISPLACEMENT MEANS AND HAVING ONE AND THEREOF EXPOSED TOEXISTING PRESSURES IN THE FIRST SOLUTION DISPLACEMENT MEANS AND THEOPPOSITE END THEREOF EXPOSED TO EXISTING PRESSURES IN THE SECONDSOLUTION DISPLACEMENT MEANS, AND MEANS FOR ALTERNATELY COMMUNICATING ONESOLUTION DISPLACEMENT MEANS TO THE HIGH PRESSURE SIDE OF THE SYSTEMWHILE SIMULTANEOUSLY COMMUNICATING THE OTHER SOLUTION DISPLACEMENT MEANSTO THE LOW PRESSURE SIDE OF THE SYSTEM TO ACTUATE THE PISTON ANDSOLUTION DISPLACEMENT MEANS BY SYSTEM FORCES ACTING ON OPPOSITE ENDS OFTHE PISTON.